The present invention generally relates to a belt transfer assembly and, more particularly, to a belt transfer assembly that transfers articles generally at a 90xc2x0 angle to the main conveyor, and which is particularly suitable for placement in line in a conveying system between conveying sections.
Transfer assemblies are typically positioned between two in-line conveyor sections, including roller or belt driven conveyor sections, and adjacent one or more transfer conveyor sections for selectively transferring articles from one of the in-line conveyor sections to the transfer conveyor sections. Transfer assemblies typically move the articles to be transferred at right angles with respect to the conveying direction of the conveyor sections.
Conventional transfer assemblies include a plurality of rollers and a plurality of grooved sheaves, which are positioned between the respective rollers. The sheaves are oriented in a direction orthogonal to the conveying direction of the rollers and are often driven by the main line drive shaft of the adjacent conveyor sections. Extending around the groove sheaves are transfer belts, which are positioned by the groove sheaves between the rollers just below the conveying surface of the rollers. When a transfer is to take place, a group of the grooved sheaves is raised such that the transfer belts positioned in the grooved sheaves are raised between the rollers to lift the articles on the rollers off the rollers and to transfer them at right angles with respect to the rollers so that the articles can be deposited on one of the adjacent transfer conveyors. It should be understood that the term xe2x80x9c90xc2x0xe2x80x9d or xe2x80x9cright anglexe2x80x9d includes clockwise and counter-clockwise 90xc2x0 directions.
In most applications, the transfer belts are raised under the article while the article is still moving. Since the article is moving at right angles to the transfer belt, the article induces lateral forces in the transfer belts. Typically, the transfer belts stop the forward motion of the article while transferring it laterally to the transfer conveyor. Depending on the size of the article being transferred and/or the shape of the article being transferred, there may be a tendency when the transfer belts engage the article for the lateral forces to induce the transfer belts to roll out of their respective grooved sheaves which results in increased wear of the transfer belts.
In addition, a conventional transfer belt typically comprises an extensible belt material, which exhibits elastic properties so that the belt can accommodate the change in length required to move between its non-transferring position and its transferring position. For example, typical belts may stretch on the order of one and a half inches in length. One problem with the more flexible belts, is that they may be pulled off the grooved sheaves when transferring an article. For example, a heavy article may cause the belt to deform locally and cause the belt to roll out of the sheaves and often break.
Consequently, there is a need for a transfer assembly which will limit the transfer belts from rolling out of their respective transfer sheaves to thereby enhance the longevity of the transfer belts and enhance the efficiency of the conveying system which incorporates the transfer assembly.
Accordingly, the present invention provides a transfer assembly for positioning between main conveyor sections and one or more transfer conveyor sections. The transfer assembly exhibits greater retention of the transfer belt in the transfer sheaves resulting in an increased life expectancy for the transfer belt while maintaining sufficient engagement with the articles being transferred to efficiently transfer the articles.
According to one form of the invention, a transfer assembly for positioning between conveyor sections includes at least two conveying devices, which define a conveying surface for at least generally aligning with the conveying surface of the conveyor sections, and a sheave assembly. The sheave assembly includes a support member, a reinforced transfer belt, and at least two transfer sheaves mounted to the support, which support the transfer belt. The support member is adapted to move the transfer belt between a non-transferring position wherein the transfer surface of the transfer belt is below the conveying surface of the conveying devices and a transferring position where the transfer surface of the transfer belt is raised above the conveying surface of the conveying devices. The transfer assembly is adapted to move the transfer belt such that the belt length of the transfer belt changes less than one quarter of an inch when moved between its non-transferring position and its transferring position.
In one aspect, the transfer belt comprises a Kevlar(copyright) reinforced transfer belt. Alternately, the transfer belt may comprise a fiberglass reinforced transfer belt. In another aspect, the transfer belt comprises a polyester reinforced transfer belt or a transfer belt reinforced by a reinforcing core, such as one or more steel cables, one or more steel cords, or other reinforcing fibers.
According to yet another aspect, the transfer belt includes a generally rectangular cross-section, and may include a plurality of projecting teeth. For example, the teeth may project from the transfer surface and/or the driven surface.
In another aspect, the sheave assembly further includes a track, with at least a portion of the transfer belt being guided through the track. The track provides additional retention of the transfer belt on the sheave assembly.
According to yet another aspect, the transfer assembly includes a lift assembly for moving the sheave assembly between the transferring position and the non-transferring position. For example, the lift assembly may include a cylinder, which lifts and lowers the sheave assembly to move the sheave assembly between its transferring and non-transferring positions. In a further aspect, the transfer assembly includes a frame, with the cylinder being pivotally mounted at one end to the frame of the transfer assembly. In a further aspect, the cylinder is pivotally mounted to the frame of the transfer assembly by a crank arm, which includes a lifter pin for selectively lifting the sheave assembly when the cylinder is actuated. In a further aspect, the transfer assembly includes a second crank arm which includes a second lifter pin. The crank arms are coupled whereby the movement of one crank arm induces movement of the other crank arm, with the first and second lifter pins selectively lifting the sheave assembly when the cylinder is actuated.
According to another aspect, the transfer belt includes a generally horizontal upper belt section which defines the transfer surface and a lower belt section. At least a portion of the lower belt section remains substantially parallel with respect to the upper belt section when the transfer belt is in either of its transferring position or its non-transferring position. In a further aspect, the transfer assembly includes a driven shaft and a drive shaft, with the drive shaft selectively driving the driven shaft and the driven shaft driving the transfer sheaves to thereby drive the transfer belt. The transfer belt preferably forms a closed loop around the transfer sheaves and the driven shaft, with the driven shaft remaining stationary when the sheave assembly is moved to its transferring position.
In another form of the invention, a sheave assembly of a transfer assembly includes a support member, a transfer belt, and at least two transfer sheaves which are mounted to the support member. The support member includes a rail. The transfer sheaves support the transfer belt, which extends through the rail, with the rail at least laterally retaining the transfer belt on the sheave assembly when the transfer belt is subject to a lateral force from an article being transferred by the transfer belt.
In one aspect, the transfer belt comprises a reinforced belt, such as a Kevlar(copyright) reinforced transfer belt, a fiberglass reinforced transfer belt, a polyester reinforced transfer belt or a steel core reinforced transfer belt, such as a belt reinforced by steel cords or cables.
According to yet another form of the invention, a transfer assembly for a conveyor system includes at least two conveying surfaces defining a conveying direction, at least two driven transfer sheaves positioned between the conveying surfaces, and a transfer belt which extends over the transfer sheaves. The transfer assembly further includes a driven belt shaft which includes a driven sheave, with the transfer belt forming a closed loop around the transfer sheaves and the driven sheave. The transfer belt is driven by the driven sheave to move in a transfer direction non-parallel to the conveying direction. The transfer assembly further includes an actuator which moves the transfer sheaves between a first position wherein the transfer surface of the transfer belt is below the conveying surface and a second position wherein the transfer surface is above the conveying surface for lifting an article being conveyed on the conveying surface and transferring the article in the transfer direction. The transfer belt has a generally horizontal belt portion which defines the transfer surface and generally horizontal lower belt portions between the transfer sheaves and the driven sheave wherein the change in length of the transfer belt is minimized when actuator moves the transfer sheaves between the first and second positions.
In one aspect, the transfer assembly includes a plurality of conveying surfaces, and a plurality of pairs of the transfer sheaves with a corresponding plurality of transfer belts.
In a further aspect, the pairs of transfer sheaves are supported by a common support. In addition, the transfer assembly further includes an actuator which moves the support between the first position and a second position to thereby move the transfer belt. Preferably, the actuator contacts the support at at least two points to maintain the transfer sheaves and the transfer belts generally level.
According to yet another aspect, the transfer assembly includes a main line drive shaft, which selectively drives the driven belt shaft. For example, the main line drive shaft may include a clutch assembly for selectively driving the driven belt shaft. Furthermore, the main line drive shaft may be adapted to selectively drive the driven belt shaft in either a counter-clockwise direction or a counter-clockwise direction wherein the transfer belt moves in a first transferring direction when the driven belt shaft is moved in a clockwise direction and moved in an opposite second transfer direction when the driven belt shaft is moved in a counter-clockwise direction.
The present invention provides an improved transfer assembly which exhibits increased retention of the transfer belt in the transfer assembly, thus extending the life of the transfer belt and improving the efficiency of a conveying system incorporating the transfer assembly.
These and other objects, advantages, purposes, and features of the invention will become more apparent from the study of the following description taken in conjunction with the drawings.